Stop devices for well conduits



May 30, 1951 J. R. BAKER 2,986,417

STOP DEVICES FOR WELL CONDUITS Filed April 14, 1958 2 Sheets-Sheet 1 Ifo. [j

INVENTOR.

TTOE/VEYS.

STOP DEVICES FOR WLL CONDUITS Filed April 14, 1958 2 Sheets-Sheet 2 HQ., a,

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United States Patent sToP DEVICES FOR WELL ooNDUrrs John R. Baker, Pasadena, ICalif., assignor to Baker Oil Tools, Inc., Los Angeles, Calif., a corporation of California Filed Apr. 14, 1958, Ser. No. 728,410

7 Claims. (Cl. 287-52.08)

The present invention relates to subsurface devices for use in well bores, and more particularly to stop devices adapted to be mounted on casing, liner, tubing, and similar conduit strings, yfor engagement with other apparatus disposed on such strings, to move the apparatus with the string longitudinall-y through Well bores.

Certain types of apparatus, such as casing centralizers, wall scratchers, cement baskets, and the like, are mounted on well casing, or similar conduit strings, for movement therewith longitudinally in the well bore as a result of their engagement with stop devices secured to the conduit strings. It is preferred to avoid welding of the stop devices to the Well conduit, since it adversely affects the physical characteristics of the conduit, and is also time consuming and relatively costly. Stop devices that have been otherwise secured to the well conduit may be relatively costly to produce, dicult or awkward to install, or incapable of transmitting substantial forces Without shifting or slipping on the conduit string.

Accordingly, an object of the present invention is to provide a stop device adapted to be mounted on a conduit string to be disposed in a well bore, which is simple and inexpensive to manufacture, easily mounted on the well conduit without welding, and yet capable of withstanding relatively large longitudinal forces without slipping when mounted on the well conduit.

Another object of the invention is to provide a stop device adapted to be mounted on a conduit string to be disposed in a well bore, which can be secured readily to the conduit string in a convenient manner.

A further object of the invention is to provide a stop device adapted to be mounted on and secured to a conduit string to be disposed in a well bore, which can be fitted appropriately to a particular size of conduit string despite wide variances in the outside diameter of such conduit string from its stated diameter.

This invention possesses many other advantages, and has other objects which may be made more clearly apparent from a consideration of several forms in which it may be embodied. Such forms are shown in the drawings accompanying and forming part of the present speciication. These forms will now be described in detail, for the purpose of illustrating the general principles of the invention; but it is to be understood that such detailed description is not to be taken in a limiting sense, since the scope of the invention is best defined by the appended claims.

Referring to the drawings:

Figure l is a side elevation of an apparatus mounted on a string of well casing disposed in a well bore, parts being shown in section and parts being broken away for purposes of clarity;

Fig. 2 is an enlarged cross-section taken along the line 2 2 on Fig. 1;

Fig. 3 is an isometric projection of a stop ring or collar device disclosed in Figs. 1 and Q;

Fig. 4 is an enlarged section taken along the line 4-4 ICC Fig. 5 is an isometric projection of another form of stop ring or collar device;

Fig. 6 is an enlarged side elevation of a joint between the sections of the ring or collar shown in Fig. 5.

The stop devices A are illustrated in the drawings by way of example as being used in conjunction with a casing centralizer B mounted on a string of well casing C, or other conduit string, positionable in a well bore D. It is to be understood that the stop devices are also useful in other relationships. For example, they may be mounted on a conduit string for engagement with Wall scratchers, cementing baskets, and other apparatus mounted on casing or similar conduit strings to be moved longitudinally through the well bore with such conduit strings.

As specifically disclosed in the drawings, the casing centralizer B is mounted on a casing section C disposed in the well bore. The centralizer can take any desired form, the one particularly shown including upper and lower longitudinally spaced collars 10, 11 slidable on the casing section, which are interconnected by circumferentially spaced outwardly bowed leaf spring members 12 welded, or otherwise suitably secured, to the upper and lower collars. The springs 12 engage the Wall of the well bore D and tend to center the Well casing therewithin.

Upper and lower stop rings 13, 14 are secured in longitudinally spaced relation to the upper and lower collars 10, 11, respectively, as by use of circumferentially spaced and longitudinally extending rigid bars 15 attached to both the collars and the rings in any suitable manner, as by a welding operation.

The particular centralizer shown is of the hinge type, in which the collars 10, 11 and the rings 13, 14 are each formed in two parts, secured to one another by diametrically opposed hinges 16. The hinges 16 on one side of the apparatus may be disconnected, by removing the hinge pins 17, which then allows the casing centralizer to be swung to open position and placed laterally around the casing section C, whereupon the centralizer can be closed and the pins 17 reinserted through the hinge knuckles, all in a known manner.

The centralizer or centering apparatus B is movable longitudinally through the well bore D upon longitudinal movement of the casing C. The stop device A is secured to the casing section C between the upper and lower stop rings or collars 13, 14 of the centering apparatus, such device being engageable with the inner edges 18, 19 of the rings to force the centering apparatus through the well bore. When the casing C is moved downwardly in the well bore, the stop device A is engageable with the upper edge 19 of the lower stop ring 14, to pull the apparatus A and its outwardly bowed springs 12 through the well bore D and past any restrictions that might be encountered therein. Conversely, movement of the casing string in an upward direction will cause the stop device A to engage the lower end 18 of the upper stop ring 13 and pull the centering device in an upward direction with the casing string within the well bore.

As speciiically shown in Figs. l to 4, inclusive, the stop device includes a stop ring collar 20, or other annular member, adapted to be secured to the casingbetween the inner edges 18, 19 of the centralizer rings 13, 14. The inside diameter of the annular member 20 is greater than the outside diameter of the casing section C, so that assurance is had that the annular member can be placed on casing sections of a particular stated size, the outside diameter of which may vary` to a substantial extent from such stated size. Thus, the annular member 20 can be placed on casing sections that may be somewhat oversize, undersize, or that are not truly round.

The stop ring is secured to the casing at the desired point thereon by means of set screws 21 disposed on one side of the ring, and lock elements 22 disposed on the opposite side of the ring. As shown, each lock element consists of a shank 23 that is preferably knurled, so that the lock element can be inserted from the interior of the ring in a companion radial bore A24 in the ring with a forced or press tit. Appropriate movement of the shank, 23 into the bore- 24 is assured by beveling the outer end 25 of the shank, the extent of outward movement within the bore being limited by engagement of .a flange 26 on the lock element with the inner surface 27 of the ring. Projecting inwardly from the flange 26 is a toothed portion 28, which is in the form of a sharp V shaped tooth having a chisel edge 29. The edge 29 is disposed transversely of the inner surface of the ring and is adapted to bite into or grip the periphery of the conduit string or well casing C.

Disposed diametrically opposite the lock element 22 is a set screw 21 that is threaded within a radial threaded hole or bore 30 in the stop ring 20. The inner portion of the set screw is formed with a cup point 31 adapted to grip the periphery of the casing, whereas its outer portion is formed with a non-circular socket 32, such as a hexagonal socket, adapted to receive a suitable wrench (not shown) for rotating the screw 21 in the threaded bore 30 and forcing it against the periphery of the casing C.

As shown, two buttons or lock elements 22 may be used, and opposite each of such buttons or lock elements is one of the set screws 21 threaded in its companion threaded bore 30.

Initially, the set screws 21 are disposed in an outward position within their threaded bores 30, so that each cup point 31 does not extend within the inner surface or Wall 27 of the ring. The extent of inward projection of the tooth 28 of each lock element 22 within the inner wall 27 of the ring is also not very great, the distance between the tooth edge 29 and the di-ametrically opposite surface 27 of the ring being greater than the diameter of the casing C, allowing the ring to be slipped over the end of the casing to the position at which it is to be fastened n thereto. After reaching such position, the set screws 21 need merely be turned to the right and tightened, the screws feeding inwardly of the ring 20 and bearing against the casing C to pull on the ring and force the teeth 28 on the diametrically opposite buttons 22 into the casing, so as to lirmly secure the ring 20 to the casing.

In the form of stop device illustrated in Figs. and 6, essentially the same arrangement of set screws 21 and lock elements 22 is used as in the other form of the invention. The main difference resides in the fact that the ring 20a, 20b, collar, or annular member, is made from two pieces, which are identical to one another, except for the type of radial hole or bore 24 or 30 provided therein. Each piece has an arcuate extent of a little more than 180 degrees, one end having a downwardly projecting tongue 35 and also an upwardly extending groove 36. The opposite end of the same piece or segment has an upwardly extending tongue 37 and a downwardly extending groove 38 adjacent thereto. The downwardly extending tongue 35 of one segment ts in the companion downwardly extending groove 38 of the other segment, the upwardly extending groove 36 at the saine end of the first segment receiving the upwardly extending hook or tongue 37 at the same end of the other segment. At the other joint between the segments 20a, 20b, the downwardly extending tongue 3S of the second segment -ts within a downwardly extending groove 38 of the rst segment, the upwardly extending groove 36 of the second segment receiving the upwardly extending tongue 37 of the rst segment.

In mounting the stop device illustrated in Figs. 5 and 6 on the well casing, the centering device B, or other apparatus, may or may not already have been disposed on the casing section C, since its initial or subsequent mounting thereon is immaterial to the attachment of the stop device to the casing. The two segments 20a, 20h of the stop collar, with the set screws 21 occupying their out- Waly threadedy position within one of the segments 20,11,

are moved laterally over the casing section C at the desired setting location, each segment being spread' apart slightly to permit its full placement over the casing in view of the fact that each segment has an arcuate extent of a little more than 180 degrees. The tongues 35, 37 are placed in their companion grooves 38, 36 to complete the collar, whereupon the set screws 21 are threaded inwardly and are brought to bear against the casing, pulling the diametrically opposite buttons 22, secured to the other segment 20a, inwardly to force the chisel edges 29- against the wall of the well casing. When the set screws 21 have been tightened sul'liciently, the two-part stop ring will have been rmly secured to the casing.

The arcuate spacing between the buttons 22 is about degrees, as shown in Figs. 1 to 4, and is about 60 degrees, as disclosed in Fig. 5, the arcuate spacing between the set screws 21 being about 90 degrees in Figs. 1 to 4, and about 60 degrees in Fig. 5. The arcuate spacing should not be too great, since it is found that the stop device yhas a greater holding force on the well casing when the lock elements 22 are arcuately closer to one another, the set screws 21 being correspondingly closer to one another and preferably diametrically opposite the lock elements.

Both forms of stop device can 'he mounted very quickly and easily on the casing. It is only necessary to slide the device with the lock elements 22 and set screws 21 mounted thereon over the casing C in the embodiment disclosed in Figs. l to 4, or move them laterally onto the casing and interlock the tongue portions 35, 37 in the form of invention shown in Figs. 5 and 6, whereupon the set screws 21 are tightened firmly against the casing to pull the transverse chisel tooth edges 29 against the casing. The operator need only stand in one position and need use only one wrench since the set screws 21 disclosed are all in essentially the same location at one side of the well casing C and are readily available to the operator, who can tighten the set screws against the casing trrnly, to correspondingly cause the opposed lock elements 22 to grip the casing. It is not necessary for the operator to move around the casing to perform a multitude of manipulations in attaching the stop device to the casing.

The stop devices disclosed will stand very substantial longitudinal forces without slipping on the well casing. The forces that can be withstood are substantially greater than the maximum forces normally encountered in an oil well in moving other apparatus, such as the centering device B, in the Well bore. Actual tests on stop devices mounted on 7-inch casing have shown that they will withstand total longitudinal forces of as much Ias 20,000 lbs., and more, prior to. their failure or slipping on the well casing.

-In connection withthe form of invention disclosed in Figs. 5 and 6, it isl to -be noted that the bottom of each groove 36, 38 is inclined in a direction toward the arcuate end of the segment and the longitudinal end of the ring, and that the hook or tongue 35, 37 is correspondingly inclined. By virtue of this arrangement, assurance is had that themating sides 40 of the tongues engage one another over a substantial surface, whereas the point 41 where the extension 42 of each segment 20a, 20b, that is of reduced width, joins the main portion of the segment is much wider than if the groove and tongue were straight across. Accordingly, the cross-sectional area at which the extension 42 is joined to the main body of each segment is much greater since the width of such point of support 41 is greater than if the .tongue and groove were made with their ends and bottom portions parallel to the longitudinal ends of the ring.

The inventor claims:

1. In a stop device to be mounted on a tubular running- `in string to be lowered in a well bore to engage an appacured to the annular member against all movement thereon and having a tooth extending inwardly of the inner wall of the annular member and lying in a plane substantially normal to the axis of the annular member; and a screw threaded into the annular member sustantially diarnetrically opposite said lock element and adapted to be threaded inwardly of the annular member to bear against the running-in string and force said tooth inwardly against the running-in string.

2. In a stop device to be mounted on a tubular runningin string to be lowered in a well bore to engage an apparatus mounted on the tubular running-in string: an annular member adapted to be mounted on the running-in string to engage the apparatus; a lock element xedly secured to the annular member against all movement thereon and having an elongate, sharp tooth extending inwardly of the inner wall of the annular member and lying in a plane substantially normal to the axis of the annular member; and a screw substantially diametrically opposite said lock element threaded into the annular member and adapted to be threaded inwardly of the annular member to bear against the running-in string and force said tooth inwardly against the running-in string.

3. In a stop device to be mounted on a tubular runningin string to be lowered in a well bore to engage an apparatus mounted on the running-in string: an annular member adapted to be mounted on the running-in string to engage the apparatus; a plurality of lock elements xedly secured to the annular member against all movement thereon and on one side thereof, each element having a tooth extending inwardly of the inner wall of the annular member and lying in a plane substantially normal to the axis of the annular member; and a plurality of threaded screws threaded into the annular member on the opposite side thereof and adapted to be threaded inwardly of the annular member to bear against the running-in string and force said teeth inwardly against the running-in string.

4. In a stop device to be mounted on a tubular runningin string to be lowered in a well bore to engage an apparatus mounted on the tubular running-in string: an annular member adapted to be mounted on the running-in string to engage the apparatus; a plurality of lock elements xedly secured to the annular member against all movement thereon and on one side thereof, each element having an elongate, sharp tooth extending inwardly of the inner Wall of the annular member and lying in a plane substantially normal to the axis of the annular member; and a plurality of screws threaded in the annular member, each screw being disposed substantially diametrically opposite a lock element, said screws being adapted to be threaded inwardly of the annular member to bear against the running-in string and force said teeth. inwardly against the running-in string.

5. In a stop device to be mounted on a tubular runningin string to be lowered in a well bore to engage an apparatus mounted on the tubular running-in string: an annular member having an inner surface and adapted to be mounted on the running-in string to engage the apparatus, said annular member having a radial bore on one side thereof and a threaded bore substantially diametrically opposite said radial bore; a lock element having a shank in said radial bore and a ange engaging the inner surface of said annular member, said lock element being secured to said annular member against all movement relative thereto, said lock element also having a tooth extending inwardly of said ange and lying in a plane substantially nor-mal to the axis of said annular member; a screw threaded in said threaded bore and adapted to be threaded inwardly of the annular member to bear against the running-in string and force said tooth inwardly against the running-in string.

6. In a stop device to be mounted on a tubular runningin string to be lowered in a well bore to engage an apparatus mounted on the tubular running-in string: an annular member having an inner surface and adapted to be mounted on the running-in string to engage the apparatus, said annular member having a radial bore on one side thereof and a threaded bore substantially diametrically opposite said radial bore; a lock element including a shank having an interference t in said radial bore to prevent all movement of said lock element relative to said annular member, said lock element having a ange engaging the inner surface of said annular member, said lock element also having an elongate, sharp tooth extending inwardly of said flange and lying in a plane substantially normal to the axis of the annular member; and a screw threaded in said threaded bore and adapted to be threaded inwardly of said annular member to bear against the running-in string and force said tooth inwardly against the running-in string.

7. In a stop device to be mounted on a tubular runningin string to be lowered in a well bore to engage an appa- `ratus mounted on the tubular running-in string: an annular member having an inner surface and adapted to be mounted on the running-in string to engage the apparatus, said annularmember having a plurality of radial bores on one side thereof and a plurality of threaded bores substantially diametrically opposite said radial bores; a plurality of lock elements including Shanks having an interference tit in said radial bores to prevent all movement of said lock elements relative to said annular member, said lock elements having anges engaging the inner surface of said annular member, said lock elements also having elongate teeth extending inwardly of said anges, each tooth lying in a plane substantially normal to the axis of the annular member; and screws threaded in said threaded bores and adapted to be threaded inwardly of the annular ymember to bear against the running-in string and force said teeth inwardly against the running-n string.

References Cited in the ile of this patent UNITED STATES PATENTS 1,493,107 Cowen May 6, l924 1,794,905 Kass Mar. 3, 1931 2,163,315 Dalrymple Ian. 20, 1939 2,836,447 Wright May 27, 1958 FOREIGN PATENTS 841,107 Germany June 13, 1952 

